Scemblix (Asciminib)
Protein kinase inhibitor for Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML-CP)
Scemblix (asciminib) is a first-in-class STAMP inhibitor used to treat adults with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase (Ph+ CML-CP). Unlike conventional tyrosine kinase inhibitors, asciminib targets the ABL myristoyl pocket of the BCR::ABL1 oncoprotein, offering a novel mechanism of action for patients who have not responded to or cannot tolerate other treatments.
Quick Facts
Key Takeaways
- Scemblix is a novel STAMP inhibitor that targets a different binding site (myristoyl pocket) on the BCR::ABL1 protein compared to conventional tyrosine kinase inhibitors.
- It is indicated for adults with Ph+ CML-CP who have not responded to or cannot tolerate at least two prior tyrosine kinase inhibitors.
- The standard daily dose is 80 mg, taken either as 2 tablets of 40 mg once daily or as 1 tablet of 40 mg twice daily approximately 12 hours apart.
- Must be taken on an empty stomach — at least 2 hours after and 1 hour before food.
- Regular blood monitoring is essential to track blood cell counts, pancreatic enzymes, electrolytes, and heart function throughout treatment.
What Is Scemblix and What Is It Used For?
Quick Answer: Scemblix (asciminib) is a targeted cancer medicine that treats adults with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase (Ph+ CML-CP). It works by blocking the BCR::ABL1 protein through a novel mechanism distinct from other CML drugs.
Scemblix contains the active substance asciminib, which belongs to a group of medicines called protein kinase inhibitors. It was developed by Novartis and received approval from the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) for the treatment of adults with CML who have been previously treated with two or more tyrosine kinase inhibitors (TKIs).
Chronic myeloid leukemia (CML) is a type of blood cancer that arises from a genetic abnormality known as the Philadelphia chromosome. This chromosomal translocation creates a fusion gene called BCR::ABL1, which produces an abnormal protein that drives the uncontrolled growth of white blood cells. In the chronic phase, the disease progresses slowly and is generally manageable with appropriate treatment, though it requires long-term therapy.
How Scemblix Works
What sets Scemblix apart from conventional CML treatments is its unique mechanism of action. While most tyrosine kinase inhibitors (such as imatinib, dasatinib, and nilotinib) work by binding to the ATP-binding site of the BCR::ABL1 kinase, asciminib targets a completely different region called the myristoyl pocket. This pocket is an allosteric regulatory site on the ABL1 portion of the BCR::ABL1 fusion protein.
By binding to the myristoyl pocket, asciminib locks the BCR::ABL1 kinase in an inactive conformation, effectively shutting down its signaling and preventing the proliferation of leukemic cells. This mechanism is referred to as STAMP inhibition (Specifically Targeting the ABL Myristoyl Pocket), and Scemblix is the first drug in this class to reach clinical use.
Because asciminib binds to a different site than conventional TKIs, it retains activity against many BCR::ABL1 mutations that confer resistance to ATP-competitive inhibitors. This makes it a valuable treatment option for patients whose disease has progressed on prior TKI therapy due to resistance mutations. In the pivotal ASCEMBL trial, asciminib demonstrated superior molecular response rates compared to bosutinib in patients with Ph+ CML-CP who had been previously treated with at least two TKIs.
What Should You Know Before Taking Scemblix?
Quick Answer: Before starting Scemblix, inform your doctor about all medical conditions, particularly any history of pancreatitis, hepatitis B, heart problems, or electrolyte imbalances. Scemblix is not recommended during pregnancy or breastfeeding.
Contraindications
You should not take Scemblix if you are allergic to asciminib or any of the other ingredients in the medicine, including lactose monohydrate, microcrystalline cellulose, hydroxypropyl cellulose, croscarmellose sodium, polyvinyl alcohol, titanium dioxide, magnesium stearate, talc, colloidal silicon dioxide, lecithin, xanthan gum, and iron oxides.
Warnings and Precautions
Talk to your doctor or pharmacist before taking Scemblix if any of the following apply to you:
- Pancreatitis history: If you have or have had severe upper abdominal pain that may be related to pancreatic problems (pancreatitis), your doctor needs to know as Scemblix can elevate pancreatic enzymes and may worsen this condition.
- Hepatitis B infection: If you have ever had or may have hepatitis B infection, inform your doctor. Scemblix may cause hepatitis B to become active again (reactivation). Your doctor will check for signs of this infection before treatment begins and may prescribe antiviral prophylaxis.
- Heart conditions: If you have any heart disease or an abnormal heart rhythm, such as a condition known as QT prolongation (visible on an electrocardiogram), your doctor must be informed before starting treatment.
- Electrolyte imbalances: Low levels of potassium (hypokalemia) or magnesium (hypomagnesemia) in the blood can increase the risk of cardiac complications during Scemblix treatment.
- Weakness, spontaneous bleeding or bruising, and frequent infections with signs such as fever, chills, sore throat, or mouth ulcers (signs of myelosuppression)
- Severe upper abdominal pain (possible pancreatitis)
- Irregular heartbeat or palpitations (possible QT prolongation)
- Headache, dizziness, chest pain, or shortness of breath (possible hypertension)
Monitoring During Treatment
Your doctor will regularly monitor your condition to ensure that the treatment is working as expected. You will undergo regular tests during treatment, including blood tests that will check:
- Blood cell counts — white blood cells, red blood cells, and platelets
- Pancreatic enzyme levels — amylase and lipase
- Electrolyte levels — potassium and magnesium
- Heart rate and blood pressure
Pregnancy and Breastfeeding
Scemblix may harm an unborn baby. If you are a woman of childbearing potential, your doctor may perform a pregnancy test before treatment begins. You must use effective contraception during treatment with Scemblix and for at least 3 days after the last dose.
If you become pregnant or think you may be pregnant while taking Scemblix, tell your doctor immediately. It is not known whether Scemblix passes into breast milk. You should stop breastfeeding during treatment and for at least 3 days after the last dose.
Children and Adolescents
Scemblix is not indicated for use in children or adolescents under 18 years of age. There is currently insufficient data on the safety and efficacy of asciminib in pediatric populations.
Driving and Operating Machinery
Scemblix has no or negligible effect on the ability to drive and use machines. However, if you experience side effects such as dizziness or visual disturbances after taking this medicine, you should refrain from driving or operating machinery until the effects have resolved.
Scemblix contains lactose. If you have been told by your doctor that you have an intolerance to certain sugars, contact your doctor before taking this medicine. This medicine also contains less than 1 mmol (23 mg) sodium per dose, meaning it is essentially sodium-free.
How Does Scemblix Interact with Other Drugs?
Quick Answer: Scemblix can interact with several classes of medications including antiepileptics, anticoagulants, certain antibiotics, immunosuppressants, and herbal products like St. John’s Wort. Always inform your doctor about all medicines you are taking.
Drug interactions can alter how Scemblix works or increase the risk of serious side effects. It is essential to tell your doctor or pharmacist about all medicines you are taking, have recently taken, or might take. This includes prescription medicines, over-the-counter drugs, and herbal products.
Major Interactions
The following categories of medicines require particular attention when used with Scemblix due to the potential for clinically significant interactions:
| Drug / Class | Examples | Type of Interaction |
|---|---|---|
| Antiepileptics (CYP3A4 inducers) | Carbamazepine, phenobarbital, phenytoin | May decrease Scemblix effectiveness |
| Herbal products | St. John’s Wort (Hypericum perforatum) | May decrease Scemblix effectiveness |
| QT-prolonging drugs | Haloperidol, clarithromycin, moxifloxacin, methadone, pimozide, chloroquine, halofantrine, bepridil | Increased risk of cardiac arrhythmia (torsade de pointes) |
| Anticoagulants | Warfarin, dabigatran | Altered anticoagulant effect; monitor closely |
| Opioid analgesics | Alfentanil, fentanyl | Altered opioid levels; dose adjustment may be needed |
| Ergot alkaloids | Dihydroergotamine, ergotamine | Increased ergot toxicity risk |
| Immunosuppressants / Antimetabolites | Methotrexate, sulfasalazine, colchicine | Altered levels of co-administered drug |
| Statins | Rosuvastatin | Increased statin levels; monitor for myopathy |
| Cardiac glycosides | Digoxin | Altered digoxin levels; monitor closely |
Food Interactions
Scemblix must not be taken with food. You should take it at least 2 hours after a meal and wait at least 1 hour before eating again. Food can significantly affect the absorption and bioavailability of asciminib, potentially altering its therapeutic effect. Water is permitted when swallowing the tablets.
If you are already taking Scemblix and are prescribed a new medicine, tell your doctor that you are on Scemblix. Similarly, if you are about to undergo surgery or any medical procedure, inform your healthcare team that you are taking this medication, as some anesthetic agents (such as alfentanil and fentanyl) may interact with Scemblix.
What Is the Correct Dosage of Scemblix?
Quick Answer: The recommended total daily dose of Scemblix is 80 mg, taken either as two 40 mg tablets once daily or one 40 mg tablet twice daily approximately 12 hours apart. It must be taken on an empty stomach.
Always take Scemblix exactly as your doctor or pharmacist has told you. Do not change the dose or stop taking the medicine without consulting your doctor first. Your doctor will determine the appropriate dose based on your response to treatment and any side effects you may experience.
Adults
Standard Dosing
The recommended total daily dose is 80 mg. You may take your daily dose in one of two ways:
- Once daily: Take 2 tablets (2 × 40 mg) at approximately the same time each day.
- Twice daily: Take 1 tablet (40 mg) followed by another tablet (40 mg) approximately 12 hours later.
How to Take Scemblix
- Swallow the tablets whole with a glass of water.
- Do not break, crush, or chew the tablets.
- Take at least 2 hours after a meal.
- Wait at least 1 hour before eating again.
- Take at the same time each day for consistency.
Depending on how you respond to treatment and any side effects you may experience, your doctor may ask you to take a lower dose or to temporarily or permanently stop treatment. This is a long-term treatment that may continue for months or years. Your doctor will monitor your condition at regular intervals to ensure the treatment is effective.
Children and Adolescents
Scemblix is not recommended for children or adolescents under 18 years of age. There are currently no clinical data supporting the use of asciminib in pediatric patients.
Elderly Patients
No specific dose adjustment is required for elderly patients. However, older adults may be more susceptible to certain side effects, particularly myelosuppression and cardiac events. Close monitoring is advised.
Missed Dose
Once daily dosing: If it is less than 12 hours until your next dose, skip the missed dose and take the next one as planned. If it is more than 12 hours until your next dose, take the missed dose and then continue as normal.
Twice daily dosing: If it is less than 6 hours until your next dose, skip the missed dose and take the next one as planned. If it is more than 6 hours until your next dose, take the missed dose and then continue as normal.
Do not take a double dose to make up for a missed one.
Overdose
If you take more tablets than prescribed or if someone else accidentally takes your medicine, contact your doctor immediately for advice. Show the medicine package. Medical care may be needed. There is no specific antidote for asciminib overdose, and treatment is supportive and symptomatic.
Do not stop taking Scemblix unless your doctor tells you to do so. Stopping treatment prematurely may allow the leukemia to progress. If you have concerns about continuing treatment, discuss them with your healthcare team.
What Are the Side Effects of Scemblix?
Quick Answer: Common side effects of Scemblix include low blood cell counts, upper respiratory infections, headache, dizziness, high blood pressure, gastrointestinal symptoms (nausea, vomiting, diarrhea), rash, joint pain, and fatigue. Serious side effects include severe myelosuppression, pancreatitis, and QT prolongation.
Like all medicines, Scemblix can cause side effects, although not everyone gets them. Some side effects may be serious and require immediate medical attention. If you experience any serious side effects, stop taking the medicine and contact your doctor immediately.
Serious Side Effects
- Thrombocytopenia (very common) — spontaneous bleeding or bruising, indicating low platelet counts
- Neutropenia (very common) — fever, sore throat, frequent infections, indicating low white blood cell counts
- Febrile neutropenia (uncommon) — fever above 38°C with low white blood cell counts
- Pancytopenia (uncommon) — low levels of all types of blood cells
- QT prolongation (uncommon) — irregular heart rhythm or abnormal electrical activity of the heart
Side Effects by Frequency
Very Common
May affect more than 1 in 10 people
- Thrombocytopenia (low platelets — bleeding, bruising)
- Neutropenia (low white blood cells — infections, fever)
- Anemia (low red blood cells — tiredness, pale skin)
- Upper respiratory tract infections
- Headache
- Dizziness
- Hypertension (high blood pressure)
- Cough
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Abdominal pain
- Rash
- Pruritus (itching)
- Musculoskeletal pain
- Arthralgia (joint pain)
- Fatigue
- Elevated lipase and amylase (pancreatic enzymes)
- Elevated liver transaminases (ALT, AST, GGT)
- Dyslipidemia (abnormal blood lipids)
Common
May affect up to 1 in 10 people
- Lower respiratory tract infections
- Influenza
- Hypothyroidism (underactive thyroid)
- Decreased appetite
- Blurred vision
- Dry eyes
- Palpitations
- Pleural effusion (fluid around the lungs)
- Dyspnea (shortness of breath)
- Chest pain (non-cardiac)
- Pancreatitis (inflammation of the pancreas)
- Urticaria (hives)
- Edema (generalized swelling)
- Pyrexia (fever)
- Elevated bilirubin (liver function)
- Elevated creatine phosphokinase (muscle function)
- Hyperglycemia (high blood sugar)
Uncommon
May affect up to 1 in 100 people
- Febrile neutropenia (fever with low white blood cells)
- Pancytopenia (low levels of all blood cell types)
- QT prolongation (abnormal heart rhythm)
- Hypersensitivity reactions (allergic reactions including rash, hives, breathing difficulties, or low blood pressure)
Abnormal Blood Test Results
During treatment, your blood test results may be abnormal. These can provide your doctor with information about how your organs are functioning. The most common laboratory abnormalities include:
- Very common: Elevated lipase and amylase (pancreatic function), elevated liver transaminases (ALT, AST, GGT), dyslipidemia
- Common: Elevated bilirubin (liver function), elevated creatine phosphokinase (muscle function), hyperglycemia (blood sugar)
Your doctor will monitor these laboratory values at regular intervals throughout your treatment and may adjust your dose or temporarily pause treatment if significant abnormalities are detected.
It is important to report suspected side effects after the medicine has been approved. This allows continuous monitoring of the medicine’s benefit-risk balance. Healthcare professionals and patients are encouraged to report any suspected adverse reactions to their national pharmacovigilance authority.
How Should You Store Scemblix?
Quick Answer: Store Scemblix below 25°C in its original packaging. Keep it away from moisture and out of reach of children. Do not use after the expiry date.
Proper storage of Scemblix is essential to maintain the medicine’s effectiveness and safety. Follow these storage guidelines carefully:
- Keep out of sight and reach of children.
- Do not use after the expiry date stated on the blister and carton after EXP. The expiry date refers to the last day of that month.
- Store at no more than 25°C (77°F).
- Store in the original packaging to protect from moisture.
- Do not use this medicine if the package appears damaged or shows signs of tampering.
Do not dispose of medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. These measures help protect the environment.
What Does Scemblix Contain?
Quick Answer: Scemblix contains asciminib (as asciminib hydrochloride) as the active ingredient. It is available as 20 mg pale yellow and 40 mg violet-white film-coated tablets.
Active Substance
The active substance is asciminib. Each 20 mg film-coated tablet contains asciminib hydrochloride equivalent to 20 mg asciminib. Each 40 mg film-coated tablet contains asciminib hydrochloride equivalent to 40 mg asciminib.
Inactive Ingredients
Both the 20 mg and 40 mg tablets contain: lactose monohydrate, microcrystalline cellulose (E460i), hydroxypropyl cellulose (E463), croscarmellose sodium (E468), polyvinyl alcohol (E1203), titanium dioxide (E171), magnesium stearate, talc (E553b), colloidal silicon dioxide, lecithin (E322), xanthan gum (E415), and red iron oxide (E172).
The 20 mg tablets additionally contain yellow iron oxide (E172). The 40 mg tablets additionally contain black iron oxide (E172).
Appearance and Pack Sizes
- 20 mg tablets: Pale yellow, round, biconvex tablet with beveled edges, approximately 6 mm in diameter, debossed with company logo on one side and “20” on the other.
- 40 mg tablets: Violet-white, round, biconvex tablet with beveled edges, approximately 8 mm in diameter, debossed with company logo on one side and “40” on the other.
Scemblix is supplied in blister packs containing 10 film-coated tablets. Pack sizes include 20 or 60 tablets. The 40 mg tablets are also available in multipacks of 180 tablets (3 packs of 60). Not all pack sizes may be marketed in every country.
Frequently Asked Questions About Scemblix
Scemblix (asciminib) is a cancer medicine used to treat adults with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase (Ph+ CML-CP). It is typically prescribed when previous tyrosine kinase inhibitor (TKI) treatments have not been effective or have caused intolerable side effects. Scemblix works through a novel mechanism that targets the ABL myristoyl pocket of the BCR::ABL1 protein.
Scemblix is a first-in-class STAMP inhibitor (Specifically Targeting the ABL Myristoyl Pocket). Unlike conventional tyrosine kinase inhibitors such as imatinib, dasatinib, or nilotinib, which bind to the ATP-binding site of BCR::ABL1, asciminib binds to the myristoyl pocket — a different allosteric regulatory site. This unique mechanism means Scemblix can work against many BCR::ABL1 mutations that are resistant to other TKIs, making it particularly valuable for patients whose disease has progressed on prior therapy.
No, Scemblix must be taken on an empty stomach. You should take it at least 2 hours after eating and wait at least 1 hour before eating again. Food can significantly affect how the medicine is absorbed in your body. Swallow the tablets whole with a glass of water — do not crush, break, or chew them.
Regular blood tests are required throughout treatment to monitor blood cell counts (white blood cells, red blood cells, platelets), pancreatic enzyme levels (amylase and lipase), electrolyte levels (potassium and magnesium), and liver function tests. Your doctor will also monitor your heart rate and blood pressure at regular intervals. The frequency of monitoring may be more intensive at the start of treatment and then gradually reduced as your condition stabilizes.
No, Scemblix may harm an unborn baby and should not be used during pregnancy. Women who can become pregnant must use effective contraception during treatment and for at least 3 days after the last dose. A pregnancy test may be performed before starting treatment. Breastfeeding is also not recommended during treatment and for at least 3 days after the last dose, as it is not known whether asciminib passes into breast milk.
Scemblix is a long-term treatment that may continue for months or years. You should continue taking it for as long as your doctor tells you to. Your doctor will regularly assess your response to treatment through blood tests and clinical evaluations. Do not stop taking Scemblix without consulting your doctor, as stopping treatment prematurely may allow the leukemia to progress.
References
- European Medicines Agency (EMA). Scemblix (asciminib) — Summary of Product Characteristics. Available at: EMA EPAR.
- Hughes TP, Mauro MJ, Cortes JE, et al. Asciminib in Chronic Myeloid Leukemia after ABL Kinase Inhibitor Failure (ASCEMBL trial). N Engl J Med. 2019;381(24):2315-2326. doi:10.1056/NEJMoa1902328
- Réa D, Mauro MJ, Boquimpani C, et al. A phase 3, open-label, randomized study of asciminib, a STAMP inhibitor, vs bosutinib in CML after 2 or more prior TKIs. Blood. 2021;138(21):2031-2041. doi:10.1182/blood.2020009984
- National Comprehensive Cancer Network (NCCN). Clinical Practice Guidelines in Oncology: Chronic Myeloid Leukemia. Version 1.2026.
- Hochhaus A, Baccarani M, Silver RT, et al. European LeukemiaNet 2020 recommendations for treating chronic myeloid leukemia. Leukemia. 2020;34(4):966-984. doi:10.1038/s41375-020-0776-2
- World Health Organization (WHO). WHO Model List of Essential Medicines, 23rd List. Geneva: WHO; 2023.
- U.S. Food and Drug Administration (FDA). Scemblix (asciminib) — Prescribing Information. 2024.
- European Society for Medical Oncology (ESMO). Chronic Myeloid Leukaemia: ESMO Clinical Practice Guidelines. Ann Oncol. 2024.
Editorial Team
This article was prepared by the iMedic Medical Editorial Team, comprising licensed physicians with specializations in oncology, hematology, and clinical pharmacology. All content is based on current international guidelines (EMA, FDA, NCCN, ESMO, ELN) and peer-reviewed research.
All medical information has been reviewed by board-certified specialists in hematology-oncology and clinical pharmacology, following the GRADE evidence framework.
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